1. Field of the Invention
The present invention relates to ballistic resistant garments, such as soft body armor vests, and a method for constructing the same.
2. Background of the Invention
In the line of duty, law enforcement officers, military personnel, and persons in similarly dangerous occupations require protection against ballistic missiles, such as bullets, shot, shell fragments, knives, and bayonets. Historically, prior art addressing these needs has provided ballistic protection at the expense of mobility, flexibility, and the ability to dissipate heat and moisture. By using heavy and rigid materials, such as steel and plastic, prior art ballistic garments have provided adequate ballistic protection, but with considerable discomfort to the user in terms of weight, thickness, stiffness, and breathability.
Various ballistic performance specifications require different minimum performance requirements to defeat numerous threat types. One example of a ballistic performance specification is National Institute of Justice (NIJ) Standard 0101.03, xe2x80x9cBallistic Resistance of Police Body Armor.xe2x80x9d This standard classifies body armor into six specific types, by level of ballistic protection performance. The six types, in increasing levels of protection, are Types I, II-A, II, III-A, III, and IV. The first four of these armor levels, Types I, II-A, II, and III-A, protect against handgun threats and are typically soft armor protective vests worn on a regular basis. Types III and IV, on the other hand, are typically hard armor that protects against the highest threats, 308 Winchester full metal jacketed ammunition and armor piercing ammunition, respectively. For each of the six NIJ threat levels, the armor must not only defeat a specified projectile type and number of shots, but also must limit a depth of deformation in a clay backing behind the armor to 44 mm or less.
The NIJ Type I provides protection, for example, against a 38 Special round nose lead bullet impacting at 850 feet/second, and a 22 long rifle high velocity lead bullet impacting at 1050 feet/second. The NIJ Type II-A provides protection, for example, against a 357 Magnum jacketed soft point bullet impacting at 1250 feet/second, and a 9 mm full metal jacketed bullet impacting at 1090 feet/second. The NIJ Type II standard provides protection, for example, against a 357 Magnum impacting at 1395 feet/second, and a 9 mm full metal jacketed bullet impacting at 1175 feet/second.
The NIJ Type III-A armor standard requires the highest protection level for handgun threats. It provides protection, for example, against 44 Magnum lead semi-wadcutter bullets with gas checks, impacting at a velocity of 1400 feet/second or less, and 9 mm full metal jacketed bullets impacting at a velocity of 1400 feet/second or less. An armor satisfying the Type III-A standard also provides protection against the lesser threat levels, Type I, Type II-A, and Type II.
Types III and IV are for high-powered ball and armor piercing projectiles, respectively, and are typically used during tactical operations where higher protection is required. Type III armor protects against 7.62 mm full metal jacketed bullets (U.S. military designation M80) impacting at a velocity of 2750 feet/second or less, while providing protection against the lesser NIJ armor level threats. Type IV armor protects against 30-06 armor piercing rounds impacting at velocity of 2850 feet/second.
Some prior art ballistic resistant garments, in combination with woven material, use reinforced plastic panels that are thick, cumbersome, and hard to conceal. In addition to hindering mobility, this construction creates a safety hazard because assailants may see the ballistic resistant garment and shoot for the head instead. An example of these types of garments are the vests manufactured by Safari Land under the product name Hyper-Lite(trademark), which incorporate panels made of a reinforced plastic hybrid, Spectra Shield(trademark). The Spectra Shield(trademark) panels are less flexible than woven material and result in a vest that is stiff, thick, and uncomfortable to wear. Further, the impermeable plastic does not ventilate and does not dissipate heat or moisture, causing additional discomfort to the user.
Other prior art ballistic resistant garments avoid the rigid reinforced plastic and instead use woven fabric panels exclusively. For example, U.S. Pat. No. 5,479,659 discloses a ballistic resistant garment made of woven fabric that produces a vest that is more flexible, concealable, and wearable than the vests using reinforced plastic. Although this type of woven fabric vest is light compared to the plastic reinforced vests, the vest still burdens the user with a considerable weight per unit area (referred to as areal density), on the order of 1.0 lbs/ft2 for an aramid fabric design vest meeting NIJ Level III-A requirements.
To further reduce areal density but maintain performance, manufacturers use stacked woven fabric made of high performance p-phenylene benzobisoxazole (PBO) fiber, e.g., Zylon(copyright) by Toyobo, Inc. Currently, the lightest-weight soft body armor is produced by Second Chance Body Armor, Inc. under the product name Ultima(trademark). In meeting the NIJ standards, Ultima(trademark) areal densities are 0.49 lbs/ft2 for NIJ 0101.03 Type II-A, 0.60 lbs/ft2 for NIJ 0101.03 Type II, and 0.77 for NIJ 0101.03 Type III-A. Although reduced in areal density when compared to other prior art, the Second Chance Ultima(trademark) is still not optimal.
Overall, a ballistic resistant garment should be comfortable to wear on a continuous basis and should provide ballistic protection meeting the applicable standards for its usage. In providing comfort, the ballistic resistant garment should be flexible, should be thin and concealable, should provide adequate ventilation allowing the user to dissipate heat and moisture, and most importantly, should be lightweight to minimize the overall burden on the user. An emphasis on comfort translates directly into improved protection, since comfortable garments will be worn much more often than burdensome garments.
The present invention is an improved fabric armor for use in ballistic resistant garments. The fabric armor is constructed of high performance fiber fabric arranged in a quasi-isotropic orientation. This quasi-isotropic orientation is more effective in dispersing the impact energy at a minimal areal density in comparison to the prior art methods that simply stack fabric plies.
The first preferred embodiment uses p-phenylene benzobisoxazole (PBO) fibers, such as commercially available as-spun Zylon(copyright)-AS, 500-denier. The PBO fiber also provides cut resistance superior to any other high performance fiber.
The second preferred embodiment uses aramid fibers, e.g., Kevlar(trademark), KM2(trademark), or Twaron(trademark).
A third preferred embodiment uses ultra-high molecular weight polyethylene fibers, e.g., Spectra(trademark) or Dyneema(trademark).
Alternating layers of the high performance fiber fabric are positioned in a quasi-isotropic orientation. This orientation produces a garment that weighs less than any previous soft fabric armor, but still provides equivalent ballistic performance in accordance with the velocity and blunt trauma specifications of NIJ Standard 0101.03. The present invention provides ballistic protection equivalent to prior art NIJ Level III-A garments with a significant reduction in areal density, i.e., a greater than 10% reduction in areal density to less than 0.69 lbs/ft2 when using the PBO fiber, when compared to the 0.77 lbs/ft2 Second Chance Ultima(trademark). Along with a reduction in areal density, the improved fabric armor provides the user with a lighter, more flexible, more compact, and more moisture vapor breathable garment.
To achieve the quasi-isotropic orientation, the high performance fiber is woven into a balanced, plain weave fabric, e.g., approximately 25xc3x9725 counts/inch and approximately 3.3 oz/yd2. Multiple layers of fabric are combined to create the ballistic filler material for a vest. The number of fabric layers is determined by the ballistic requirement, e.g., the NIJ level required. The individual fabric layers are alternated so that the warp and fill direction of one fabric layer is oriented at a substantially different angle to the warp and fill direction of the second layer. A substantially different angle ranges from 20-70xc2x0, in which range examples of suitable angles of orientation include 45xc2x0, 22.5xc2x0, 30xc2x0, 60xc2x0, and 67.5xc2x0. The positioning of each ply with respect to adjacent plies creates the quasi-isotropic orientation.
As an alternate to positioning fabric layers at angles of orientation, the fabric itself may be formed with its fiber oriented into an angle other than 0/90xc2x0 to create the quasi-isotropic orientation. This orientation may be accomplished using novel weaving methods or methods other than weaving.
The woven fabric is cut to match the size and shape of each vest component, thereby providing a tailored fit. Fabric cutters cut all of the raw materials for the ballistic filler, covers, and carrier.
The multiple layers of oriented, cut fabric are then preferably quilted through with stitching, e.g., 1 to 2 inch diamond stitching using high performance thread such as Kevlar(trademark). The stitching covers the entire ballistic filler material area of the vest. Although preferred, stitching is not required for the present invention to achieve its intended performance.
The ballistic filler is then placed inside a cover for environmental and ultraviolet protection. The filler and cover are then placed in a fabric vest carrier that is designed to be worn underneath a uniform or shirt for concealable protection. The CoolMax(trademark) by Dupont is an example of a suitable vest carrier fabric that is worn on the inside surface of the carrier, while a poly/cotton blend fabric is typically used for the external surface of the carrier. The carrier is sewn together with adjustable shoulder and side straps. Preferably, the webbing is nylon and the fasteners are all hook and loop.
The invention works in the following manner. The ballistic filler provides the ballistic protection. When a bullet or other projectile strikes the vest, the kinetic energy from the projectile is transferred into the ballistic filler fabric. The quasi-isotropic orientation of the fabric plies provides a widespread dissipation of the energy and greatly reduces blunt trauma. The fibers within the fabric are pulled and the quilting or stitching of the fabric plies further reduces the blunt trauma as defined by the depth of deformation in a clay backing.
Accordingly, it is the object of the present invention to provide ballistic resistant fabric armor of previously unattainable minimum areal density, bulk, and thickness that still meets global ballistic standards, e.g., the NIJ velocity and blunt trauma specifications, Standard 0101.03 Type III-A and lower.
It is another object of the present invention to provide ballistic resistant fabric armor that is flexible, allowing the user to move freely and perform all functions that could be performed without the armor.
It is another object of the present invention to provide a ballistic resistant fabric armor that is well ventilated, breathable, and allows for dissipation of heat and moisture, thereby keeping the user cool and comfortable in hot climates.
It is another object of the present invention to provide a ballistic resistant fabric armor of minimum thickness and bulk such that its use under other garments is inconspicuous.
It is another object of the present invention to provide a woven fabric ballistic resistant armor using any commonly available high performance fibers (e.g., Zylon(copyright), Kevlar(trademark), Twaron(trademark), Spectra(trademark), Dyneema(trademark), or KM2(trademark)) arranged in a quasi-isotropic orientation.
It is another object of the present invention to provide a multi-purpose protective garment using puncture and/or cut-resistant fabric armor.
It is also an object of the present invention to provide a ballistic resistant garment that may be stitched through the entire filler, making the garment easier to assemble than the more labor-intensive construction of prior art fillers in which two or more separate filler packets are quilted together. Additionally, the present invention may be used with any stitching method or without stitching entirely, because it functions independently of the stitching method.
These and other objects of the present invention are described in greater detail in the detailed description of the invention, the appended drawings, and the attached claims. Additional features and advantages of the invention. will be set forth in the description that follows, will be apparent from the description, or may be learned by practicing the invention.